There are applications where it is desirable to produce an object having a varying hardness along the length of the object. For example, there is a requirement in some applications to produce a graduated hardness pattern along the length of a brass cartridge case (a.k.a., “cartridge”) from the tip to the base of the cartridge. One process for producing a varying hardness of a cartridge involves multiple steps. In one step, a general hardness is produced over the whole length of the cartridge and is usually done using an oven. In another step, the tip of the cartridge is annealed, and this is usually done using flame heating or induction heating. An advantage of producing a graduated hardness pattern along the length of the cartridge is that allows for an increase in the propellant charge, therefore increasing the muzzle velocity of the ammunition.
What is desired is an improved system and method for producing an object having a varying hardness along the length of the object.